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Power quality analyses in the last years has assumed more and more heaviness in industrial environments, due to the presence of non-linear and unbalanced loads: they require measuring instrumentation with large bandwidth. Since voltage and current transducers are the first part of a measurement chain, they must have frequency bandwidth sufficient for analyzing conducted disturbances on power system...
Impedance analyzers are efficient in acquiring wide range impedance measurements in a wide frequency range. However, when measuring low impedances, short circuits used for compensation process can't be considered as ideal and analogue problem appears for open circuit compensation. Fortunately, because impedance matrix of a two-port passive circuit is symmetrical, characterizing this circuit by four...
Up till now, the best linear approximation (BLA) has always been determined in the frequency band where a device-under-test (DUT) operates. For the development of complete high-level design models, however, it is mandatory to know the BLA outside this frequency band. In this paper a measurement technique is proposed to extract the in-band as well as the out-of-band BLA of a nonlinear microwave amplifier...
The vortex flowmeter is widely used due to its unique advantages, but the acquirement and measurement of vortex flowmeter signal in low velocity have not been resolved yet. Wavelet transform is gaining great popularity for denoising and has been proven to be an effective method to extract signal from noise. Based on multi-resolution analysis (MRA) and vortex flowmeter signal, a modified soft threshold...
Designing, optimizing and producing modern power amplifiers (PA) requires new and fast RF (radio frequency) measurement techniques capable of characterizing its real behavior. PAs are a truly multidimensional device where many desired performance parameters are contradictory to each other. This is especially true for the generation of modern communication PAs that require high efficiency, high linearity...
This work describes the measurement of the frequency response of the wavelength modulation in a laser diode, for application in a closed-loop interferometer. The wavelength modulation is derived by the measurement of the interferometric phase, while the frequency response is estimated by means of frequency-domain model identification techniques.
Steel fiber reinforced concrete structural elements represent very interesting materials which employment has led to tangible advantages in construction technologies over the last decades. The behaviour of this kind of materials is strictly related to the fiber dispersion inside the cementitious matrix. For this reason, in the last years different non destructive measurement methods have been proposed,...
An advanced automated calibration technique for a trimming inaccuracy (calibration tolerance) of low-cost quartz resonators that are using in the Universal Sensors and Transducers Interface (USTI) integrated circuits for precision frequency (period)-to-digital conversion is described in the paper. It was shown that such technique can be used also for reducing an error due to a quartz crystal aging...
We present the results of an analytical study aimed at characterizing the mutual inductance M of Rogowski coils for generic paths of the primary wire and for nonuniform windings. In order to obtain such data, we performed a series of calculations based on the method of the mutual partial inductances and on the application of the Biot-Savart-Laplace law. Finally, we discuss the role of some critical...
This paper describes and compares two particle excitation methods, square and sine wave, used in conjunction with novel application of Phase Doppler Anemometry (PDA) to obtain particle size and charge simultaneously in real time. Different signal processing strategies for particle velocity and size estimation are investigated, including Quadrature Demodulation (QD), spectral analysis and correlation...
This paper studies the measurement of magnetism in composite resonator structures. First, we report the main steps of a theoretical analysis developed by the authors in a recent study showing how a composite resonator structure can lead to obtain unusual magnetic behavior in the low and industrial frequency ranges. Then, we describe the single unit-cell setup and the resonator structure adopted for...
A new procedure to estimate the value of the individual components of a two-terminal impedance network is presented. It is based on the application of genetic algorithms to the spectral fitting of the impedances' model. The expanded uncertainty of the estimated parameters is obtained through simulations and the algorithm is also applied to the measured frequency response of two impedance networks...
A determination of the reference impedance for the three standards line-attenuator-reflect (LAR) on-wafer vector network-analyzer (VNA) calibration is proposed. As a result, it is shown that the reference impedance to which the LAR calibration is referred cannot generally be determined. Based on this consideration, a modified LAR calibration allows a precise determination of the reference impedance...
The purpose of this work was to demonstrate the range imaging properties of a time-of-flight (TOF) 3D camera with a cooperative object. The performance of the 3D camera was characterized by measuring its distance response using a passive object within its unambiguous operating range of 1.5 - 6.5 m (20 MHz modulation). Characterization measurements were also made with a cooperative object. Besides...
Several wireless systems and networks share the same or contiguous frequency bands to provide wideband connectivity. Due to the different channel access techniques, the related communication signals are often transmitted, at the same time, over frequency intervals partially or fully overlapping to one another. In such cases, classical approaches either in the frequency or joint time-frequency domain...
A measurement system based on microwave transition analyzer (MTA) as a receiver is proposed for time domain and frequency domain characterization of linear and non-linear N-port microwave devices. The proposed measurement system is able to perform full S-parameters characterization for N-port devices with only one measurement connection step. The system is also sensitive to the input power variation...
In this paper, the exponentially damped sinusoidal signals are analyzed. The peaks of the discrete Fourier transform (DFT) results are adopted to obtain the parameters. Simple algorithms for fast measurement and estimation of an unknown damping beside frequency are presented. The idea of the quotient interpolation for the two-point frequency estimation can be adopted also for the damping. The Hann...
This paper is concerned with the characterization of depth profiles defects in metallic structures. Experimental work using giant magnetoresistors (GMR) scanning automatically a metallic plate with eddy currents induced by an excitation coil has been carried out and is described. The results are analyzed in comparison with the simulation results obtained with a commercial finite element model for...
The paper presents the approach to the design of the virtual instruments performing parallel computations for signal processing. Based on the example of the virtual instrument performing both frequency and time measurements, the method of creating the measurement software working under the real-time operating system is explained. Comparison between the designed instrument and its non-parallel counterpart...
Two major difficulties are affronted when one looks for designing a suitable equalizing system for room acoustics. The first difficulty comes from the high variability of room transfer functions (RTFs) depending on the relative source/listener position. The second problem resides in the RTFs themselves, which are characterized by a high mode density specially at high frequencies. This paper presents...
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